Tapping machine



Sept. 13, 1932- E. WLLER TAPPING' MACHINE Filed Jan. 23, 1931 2 Sheets-Sheet INVENTOR vG. E. MILLER 1,877,251

I TAPPING MACHINE Filed Jan, 23, 1931 2 Sheets-Sheet 2 Patented Sept. 13, 1932 UNITED STATES GEORGE E. MILLER; or ETNA, PENNSYLVANIA "'mrrme MACHINE Application filed January 23, 1931. Serial'No. 510735.

My invention'r'elates to apparatus for tapping couplings. 1

p The principal object of this invention is to provide an improved apparatus whereby couplings may be tapped from their centers in each direction, the threads being tapered inthesame-direction- When couplings are tapped from each end toward the center the threads at thecenter of the coupling cross each other and, produce more or less rough nessi. When pipes are screwed *into such couplings the threads on the pipes are injured by the roughness and cross-cutting of the threads. It is another object of this invention to provide by a novel means an appara tus whereby the threads may be made smooth from one end-ofthe coupling to the other so that pipes'when screwed into the couplings will not be damaged. Other objects'appear hereinafter.

Referring to the accompanying drawings,

Fig. 1 is a front view of a fragment of a machine containing my invention, parts being broken away, and omitted; Fig. 2, a view of the lower portion of Fig. 1 with the mandrel locked in its upper position; Fig. 3, a side view of'Figql withstill more parts omitted and broken away; Fig. 4, a plan view of the.

,mechanism for-holding a coupling in position fortapp'ing, a portion being broken away; Fig. 5, a section on the line 5-5 on Fig 4; Fig. 6, a side view similar to that shown in Fig. 3 but with the mandrel lowered and thecoupling holding, means moved to the left so that itmay be reversed; Fig. 7,.

an enlarged. central longitudinal view of a coupling shown in section together with the mandrel in position for a tapping operation and the tapping head lowered into the coupling to position it slightly above that which it assumes at the beginning of a tapping op eration; and Fig. 8, a top view of the upper face of the lower cap for the tapping head.

on the drawings, 1 designates the frame of the tapping machine which has the upper horizontal arm 2 carrying the vertically movable and rotatable chuck or die holder 3 havif'ig the vertical threadingdies 4 in slots 5 i They are supported by the bottom plate 7 connected to the die holder by screws. The bottom plate is provided with four springs 8 which press inwardly against the lower recessed ends 9 of the dies in order to urge the dies toward their collapsed position. The hollow die holder 3 has near its lower end the follower 10 which carries at its lower end I the reduced downward extension 11 which stands between the upper ends of the dies and centers them except during threading operations. j

The .frame 1 carries the plate 12 which carries the horizontal sliding member 13 having tongue-and-groove connections with the plate at each edge so that the member 13 may be moved horizontally beyond the plate 12 where as shown in Fig. 6 it may be rotated on the horizontal bar 14 which is slidable in the lug 15 attached to the upper side of the plate 7 12. The bar It has-a head 16 which prevents it from being drawn entirely through the lug 15. This head also acts as a stop to position the plate 12 properly for its rotation.

The sliding member 13 has the fixed jaw 17 to engage one side of the coupling 18 and the sliding jaw 19 to engage the opposite side thereof. The movable jaw 19 operates by the screw 20 threaded in the front bar 21 of the member 13, the screw 20 is operated by so the hand-wheel 22. The parts just described are so proportioned and located that when a coupling is clamped between thejaws 17 and 19 and the member 13 is pushed inwardly at positioned directly under thedie holder 3. In this position the coupling cannot be rotated since it is held fast in one direction by the jaws 17 and 19 and in the direction at right angles thereto by the described tongueand-groove connections.

The frame 1 supports the two depending guide rods 23 arranged atopposite sides of. an imaginary line e;;tending downwardly from the axial center of the dieholder 3 and of the coupling 18 when the'latter is in position for a threading operation. The lower end of the bars 23 support the horizontal bar 2 1 which carries the upstandingrapered mandrel 25 which may be adjusted vertically 1 by means of the nuts 26 and 27. When the bar 24 is supportedby the lower ends of the guide rods 23 the upper end of the mandrel 25 is below the lower end of the coupling when in its normal position for threading as shown in Fig. 1. The bar 24 has the downwardly extending leg 28 having its lower end upon one end of the lever 29 pivoted between its ends at 30. The right hand end of the lever 29 serves as a pedal by which the bar 24 may be raised on the guide rods 23 to the position shown in Fig. 2. \Vhen the bar 24 is in the position shown in Fig. 2 it is locked by the two bolts 31 supported by the brackets 32 pendent on the lower side of the frame 1. The bolts 31 are connected-together by the cross-piece 33 and operated by the handle 34.

11011 the bar 24 is locked by the bolts 31 in its upper position as shown in Figs. 2 and 3 the mandrel 25 is positioned within the coupling as shown in Fig. 3, and the die holder 3 with its dies 4 is within the coupling.

' 11 on the follower 10 and Preferably the die holder and diesare first lowered into the coupling to about their positions shown in Fig. 7. Then the mandrel is moved to its upper position as shown in Fig. 3. .In so moving, the mandrel goes up between the dies 4 and spreads them apart to their proper working positions. The die holder or spindle 3 is rotated in the usual manner and descends, threading the coupling from its central portion to its lower end, the dies riding down on the tapered mandrel and being forced gradually outwardly so as to form a tapered thread within the coupling. The upper end of the mandrel when moved upwardly as described engages the extension pushes it up above the dies 4.

At the close of the threading of one end of the coupling the handle 34 is operated to remove the bolts 31 from beneath the bar 24 so that the latter with the mandrel 25 drops to the position shown in Fig. 1. The die holder 3 is moved upwardly in usual manner as the dies have become collapsed by the action of the spring 8. The follower extension 11 drops again between the upper ends of the dies 4. Both ends of the coupling are entirely free from the dies 4 and the mandrel 25 so that when the hand wheel 22 is seized the member 13 may be drawn out of the plate 12. It may be then rotated on the bar 14 until the member 13 and the coupling have been turned bottom-side'up. Then the member 13 is slid back into the plate 12 and the coupling again is positioned above the mandrel 25 and below the die holder 3. The die holderis again lowered with the coupling. The lever 29 is again operated to elevate the bar 24 and the mandrel 25 which are locked in their upper positions by the bolts 31, as before. The lower half of the coupling is then threaded in the same manner as its upper half was. At the conclusion of this threadsures that there will be no roughness or crossthreading at the center of the coupling to mar the ends of pipe screwedinto -them.

I claim:--

, 1. In a machine for threadingcouplings from their centers outwardly, a rotatableand reciprocabledie holder,- dies carried-thereby and movable radially, a coupling holder constructed to hold a coupling'with its axial center line in axial alinement with thedie holder, and a mandrel positioned "when idle at the opposite side of the coupling holder from the die holder and tapering toward the die holder and wholly and movable longitudinally into a fixed position in the axial centerline of the coupling, the dies surrounding and contacting with the surface of the mandrel as the die holder;

feeds the dies from the centerof a coupling;

outside of the same in the coupling holder to one end thereof,'the

said holder being rotatableto bringthe opposite ends of the coupling into working, positions. I a f 2. In a machine for threading couplings from their centers outwardly, a' rotatable. and reciprocable die holder, dies carried thereby and movable radially, a; rotatable coupling holder constructed to hold a coupling with its axial center line in axial 'alinement with the die holder, and a-mandrel positioned when idle at the opposite's'ideofthe coupling holder from the die holder and tapering toward the die holder and wholly outside of the same and movable longitudi nally into a fixed position in the axial center line of the coupling, the dies surrounding and contacting with the surface of the mandrel as the die holder feeds the dies frorn'the center of a coupling in the couplingholder' to one end thereof, in combination with means whereby the coupling holder with a' coupling therein may when the mandrel is, in its idle position be rotated to bring either end of the coupling in line with the mandrel and the die holder. v

3. In a machine for threading couplings from their centers outwardly, a rotatable coupling holder, 11. die holderat one side of the coupling, a reciprocable ma'ndrelat the opposite side of the coupling holder and tapering toward the die holder, the free'encl when the mandrel is in its idle position, a

member holding the coupling holder in a fixed posit-ion, means whereby the coupling holder can be moved laterally away from the threading position of the coupling when the die holder and the mandrel are in their idle positions, whereby the coupling holder can be rotated and replaced in its working position in the said member, and radially arranged dies in the die holder separately so that they may have their inner edges engaging with the slide upon the mandrel as the die holder is fed during a threading operation.

In testimony whereof, I hereunto afiix my signature.

GEORGE E. MILLER. 

